156 NEW YORK STATE MUSEUM 



oxid in the green beds has been reduced and there the green 

 glauconitic color appears throughout. In the same way the 

 color of the green streak in the red shale, above noted, has 

 been produced. 



Regarding the origin of the glauconite in the Vernon shale 

 the writer ventures to suggest that the conditions for its for- 

 mation were very favorable such as the deposition of the fine 

 ferruginous sediments _very slowly and uniformly at the so 

 called '' mud line," in the presence of decomposing organic 

 matter. Since the waters were rather highly saline and since 

 no trace of fossil shells has been found, it is conjectured that 

 the organisms were plants of the seaweed type. It is well known, 

 especially by the studies of the Challenger^ expedition, that 

 greenish glauconite muds are now forming in the presence of 

 decomposing organic matter over considerable portions of the 

 ocean bottom, particularly near the borders of the continental 

 shelves. In the case of the Vernon shale there was an excess 

 of ferric oxid over that necessary to the formation of the glau- 

 conite and the dehydration of this excess oxid, as above ex- 

 plained, has given rise to the red color of the shale. 



In Kirkland glen an interesting example of the effect of mod- 

 ern decomposing organic matter has been observed by the writer. 

 Along a joint plane for 6 or 8 feet the ferric oxid has been re- 

 duced so that, for an inch either side of the joint plane, the 

 shale is green. This is thought to be a purely superficial effect 

 since the hillside is heavily covered with humus and surface 

 waters charged with humic acids have traveled along the joint 

 plane thus causing a reduction of the ferric oxid so that the 

 green glauconitic color is brought out. 



"■op. cit. p. 385-91- 



